The invention relates generally to an apparatus for measuring the range of motion of an articulated joint. In particular, the invention concerns a device for determining the flexure angle between adjacent, jointed body parts, as a function of the linear distance between two points, one each located on each of the body parts.
Arthrometers measure joint motion. Generally, two types of arthrometers are currently available: passive arthrometers for measuring joint motion of another person, and automatic arthrometers for measuring one's own joint motion. Typically, passive arthrometers are referred to as goniometers.
The need to measure joint motion frequently occurs during rehabilitation therapy. For example, patients participating in post-operative therapy following knee surgery are often instructed to perform standing or supine knee-bends from between thirty to eighty degrees. Once such a patient is discharged from the hospital and large, complex automatic arthrometers are no longer available to the patient, the actual flexure angle is typically determined by mere guesswork.
Simple, automatic measurement of joint motion during exercise has not been heretofore available. Neither has there been available mechanisms for indicating actual range of motion and counting repetitions in an exercising cycle. Accordingly, individuals who have been discharged from a health care facility and instructed to maintain a therapeutic exercise regimen, have been faced with great difficulty in implementing that regimen.
It is an object of the invention, therefore, to provide a simple device for measuring joint motion which is easily used by an unskilled operator. Another object of the invention is to provide such a device which is able to compensate for improper arrangement about a user's joint. Yet another object of the invention is to provide a device for measuring joint motion and for counting cycles in an exercise regimen.